Theoretical Considerations in Developing Amorphous Solid Dispersions

Use of the Flory–Huggins theory to predict the solubility of nifedipine and sulfamethoxazole in the triblock, graft copolymer Soluplus

“…Materials were dried by storage in a desiccator over calcium sulfate for at least 1 week prior to mixing. NIF, in particular, was kept in an amber bottle to prevent photodegradation 28,29,35,36 .…”

“…The interaction parameter, , has been considered a constant 16,24,26 , dependent on temperature 27,28 , or influenced by both temperature and the composition of polymer blends 15,26,[29][30][31] . However, it is typically assumed that the interaction parameter is a function of temperature only and that the respective concentrations in the mixture do not affect it 4 .…”

Challenges to improve the biopharmaceutical properties of poorly water-soluble drugs and the application of the solid dispersion technology

“…A solid dispersion is a dispersion, in the solid state, of a drug (or more than one) in a matrix formed by a hydrophilic carrier (or by an association of carriers). Solid dispersion technology has been successfully applied in the development of formulations aimed at the improvement of the dissolution profile and bioavailability of poorly water-soluble drugs [13,32,33,34,35,36,37]. Mechanisms that can be involved are the reduction of drug particle size, possibly down to the molecular level; the increased wettability of the drug; formation of soluble drug-carrier complexes; and amorphization of the drug [13,34].…”

“…Solid dispersions are classified in eutectic mixtures, solid solutions, glass solutions, or glass suspensions [35] whose definitions and mechanisms for drug dissolution improvement are presented in Table 2. Solid dispersions are also classified into four generations based on the advancement of knowledge and complexity of the system [13] as compared in Table 3 and described in 3.1.…”

“…The drug dissolution rate is still increased compared to the crystalline form of the drug since the drug is still in the amorphous state in the glass suspension. [35].…”